For Fedora, PCLinuxOS, and the rest of the Red Hat extended family, add them to /etc/pam.d/system-auth. SUSE goes its own way entirely. Add uinput to /etc/modules, or whatever your system needs to load modules at boot, and reboot.

Now what happens? My T61 runs PCLinuxOS, and the graphical login manager has absolutely no clue about fingerprint readers. kdesu doesn't know what to do with it, either. So I can't login to a graphical session with my fingerprint. However, at the console prompt I got this:

Hurrah! And it worked. It's still a baby and has lot of growing up to do, so please visit Resources for more help and updates. ThinkFinger needs more PAM modules to make it work with different types of authentication and applications, so if you're looking for a FOSS project to support that would be a good one.